Materials having volume resistivity of 106 to 1012 Ωcm which is at the level intermediate between the volume resistivity of metals and that of insulating materials, are generally called “semiconductive resins”. Semiconductive resins, with their advantages in antistatic property, dust-adsorption preventing property and the like, are used fields where static control is required, for example, such a material is used as resin material for charging components like charging rolls, charging belts and discharging belts of image formation devices such as electrophotographic copiers and electrostatic recording devices and like containers for transporting semiconductor components. However, recently, for the purpose of enhancing transcription efficiency of the copier and obtaining clearer images or slowly eliminating static electricity from precision components, it is required to control the volume resistivity to a very narrow range such as 1010 to 1012 Ωcm in semiconductive region.
Generally, examples of method for imparting conductivity to an electrically insulative resin include (1) a method of adding surfactant, (2) a method of converting the resin into alloy with a hydrophilic polymer having a conductive unit in its molecule and (3) a method of mixing the resin with conductive material such as metal or carbon material.